You dont need to endorse another ME on the DGCA CPL so that you have ME IR on the renewed CPL
Airlines like IndiGo only look for ME IR to be endorsed on the license but the IR need not be valid
If you still wish to get a new ME IR then first pass the DGCA Tech specific for the same then contact a flight school which has the same aircraft .
You are looking at about 11 hours of flying on type to get a new one endorsed
Yes RTR P can be renewed if you have 30 hours of flying experience within the last 3 years
or
Pass Part 1 of the WPC exam